Causes

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A number of disorders can result in a scrotal mass or an abnormality in the scrotum, including:

Testicular cancer. Testicular cancer is a tumor containing abnormal testicular tissue, which can usually be felt as a lump in the scrotum. Although most tumors don't cause other symptoms, some men experience pain or swelling.

Spermatocele. Also known as a spermatic cyst or epididymal cyst, spermatocele is a typically painless, noncancerous (benign), fluid-filled sac in the scrotum, usually above the testicle.

Epididymitis. This is inflammation of the epididymis, the comma-shaped structure above and behind the testicle that stores and transports sperm. Epididymitis is often caused by a bacterial infection, including sexually transmitted bacterial infections, such as chlamydia. Less commonly, epididymitis is caused by a viral infection or abnormal flow of urine into the epididymis.

Orchitis. This is inflammation of the testicle usually due to a viral infection — most commonly mumps. When orchitis is caused by a bacterial infection, the epididymis also might be infected.

Hydrocele. Hydrocele occurs when there is excess fluid between the layers of a sac that surrounds each testicle. A small amount of fluid in this space is normal, but the excess fluid of a hydrocele usually results in a painless swelling of the scrotum.

In infants, a hydrocele occurs usually because an opening between the abdomen and the scrotum hasn't properly sealed during development. In adults, a hydrocele occurs usually because of an imbalance in the production or absorption of fluid, often as a result of injury or infection in the scrotum.

Hematocele. Hematocele occurs where there is blood between the layers of a sac that surrounds each testicle. Traumatic injury, such as a direct blow to the testicles, is the most likely cause.

Varicocele. This is the enlargement of the veins within the scrotum that carry oxygen-depleted blood from each testicle and epididymis. Varicocele is more common on the left side of the scrotum because of differences in how blood circulates from each side. A varicocele might cause infertility.

Inguinal hernia. This is a condition in which a portion of the small intestine pushes through an opening or weak spot in the tissue separating the abdomen and groin. In infants, an inguinal hernia usually occurs because the passageway from the abdomen to the scrotum has failed to close during development. An inguinal hernia might appear as a mass in the scrotum or higher in the groin.

Testicular torsion. This is a twisting of the spermatic cord, the bundle of blood vessels, nerves and the tube that carries semen from the testicle to the penis. This painful condition cuts off blood to the testicle and can result in the loss of the testicle if not promptly treated. The affected testicle might be sideways, enlarged and higher than normal.

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